Opinions on the lyman moly coating system?

[Max Heat]

Being that I am one of those folk who has that pesky "need for speed", I (almost exclusively) run nosler 120gr ballistic tip 7mm rounds, out of a rem mag, and will be stepping up to ultra mag, when my new barrel arrives. In terms of heat, that will put me into a new league. But it is going to be really hard on the barrel's throat, and I am trying to think of methods to maximize it's useful life, as I don't plan on shooting light loads, after the barrel is broken in.

I am debating whether or not to start moly coating my bullets, as that is supposed to help extend barrel life. But is it really a worthwhile endeavor? Also, lyman states that the moly-coated bullets will result in lower pressures being generated, which I look at as a GOOD thing. But perplexingly, they state that velocity will also be lower with moly coating. It doesn't make sense to me that a bullet that generates less friction going down the barrel will have LOWER velocity. Is it possible that it is a mis-print? If not, could someone please explain to me why that would be?

 

[rscott5028]

Or, you could try snake oil.
...pretty much the same thing.

 

[Mikecr]

It's true(initially reduced velocities).
Moly flashes off with latent heat that cools the charge a bit. Most compensate with a bit more powder, which negates barrel life extension.
Moly also fills cracking edges, which reduces bullet jacket damage, extending life w/resp to copper fouling out only. That's good.
But a reason to stay clear of it is that it's intensive to manage both best performing coating amount, and cleaning to keep eventual bore restriction from forming. Once this restriction forms, you can't get it cleared without damaging the bore! It is wasted at that point.

Most shooters who coat have moved on past moly to WS2 or HBN. But these do not extend barrel life. I don't know of anything that does without a cost in velocity(your concern).

 

[Max Heat]

OK, it looks like it's probably not worth the trouble then, especially considering the risks associated with excessive build-up, should it occur. But I have already purchased some "snake cream" if you will, for the bore (also a Lyman product, but way cheaper than the bullet coating system). My reasoning was that MOLY-ON-MOLY should make for an ideal slippery interface between copper jacket and bore, while at the same time slowing down the rifling lands in the throat from becoming toast. But it looks like I'll have to re-think THAT theory, if there could be possible excessive build-up issues, and cooling of the charge, which apparently is what reduces the velocity.

What I see coming out in the wash here is that in the throat, where the heat is most intense, the stuff will burn up, offering no protection to the rifling lands. But progressing towards the muzzle, less-and-less of it will burn up, and more-and-more will build up, increasing the possibility of things going TOO tight, resulting in excessive pressure. But if that's the way it goes down, a "choke" effect would be formed inside of the bore, possibly offsetting the accuracy loss caused by the toasting and rub-off of the lands in the throat. But I dunno, sometimes I tend to over-think stuff like this.

As of now, I know nothing about WS2 or HBN. Looks like I'll have to spend some time looking into them. I have used PTFE-based bore treatment (Action Product's Friction Block) occasionally though, and I still have some left in the bottle that I purchased from Bob Hart, 15 or 20 years ago. I can still remember the way he used his fingers to form a circle that went from big to small, saying how it will make my group sizes shrink. But the stuff doesn't seem to be on the market any more. I take it that the reason is that you could also run into excessive buildup issues with that stuff.

 

[Mikecr]

Coatings are still useful for reducing copper, but not really for barrel life extension.
If needing to outright abuse a bore, I'd give melonite barrel coating a try.